Prosperity: new upgrade to protect smaller families

Prosperity grew everyday and its player’s number too. So, we can see some problems that have to be fixed to protect all the players.
We’ve notice that two families have conquered the entire Prosperity’s map, so the little ones can’t easily play.
Now, every family can conquer the 30% of cities on the map. If this level will be passed, the game will remove the excess by removing the oldest achievements.